Lentil Shepherd’s Pie with Creamy Cauliflower Crust — Vegetarian & GF

Cauliflower crust:

• 1 garlic clove, peeled and smashed
• 1 medium parsnip, peeled and finely chopped
• 1/2 cup whole milk
• 1 2-pound head cauliflower, cored and cut into florets
• Salt
• 3 tablespoons butter
• 2 teaspoons fresh lemon juice

Filling:

• 2 tablespoons extra virgin olive oil
• 1 medium onion, finely chopped
• 2 medium carrots, finely chopped
• 1 celery stalk, finely chopped
• Salt and freshly ground black pepper
• 8 ounces cremini mushrooms, sliced 1/4-inch thick
• 1 tablespoon tomato paste
• 3 garlic cloves, minced
• 2 teaspoons chopped fresh thyme
• 1 1/2 cups (9 ounces) cooked lentils
• 1/2 cup dry red wine
• 1/2 cup low-sodium vegetable or chicken broth
• 1/2 teaspoon sherry vinegar
• Pinch of sugar
• 1–2 teaspoons truffle oil (optional)
• 1 cup shredded Gruyère or Comté cheese

For the cauliflower crust

1. Place the garlic and parsnip in the bottom of a medium saucepan and pour in the milk. Pile the cauliflower on top, season with salt, and bring the milk to a boil over high heat. Reduce to a simmer, cover, and cook, stirring occasionally, until the cauliflower is very tender, about 20 minutes. While the cauliflower cooks, prepare the filling.
2. Transfer everything from the pot, including the cooking liquid, to a food processor. Add the butter and process until smooth and creamy. Add the lemon juice and pulse to combine. Season with salt to taste.

For the filling

1. Preheat the broiler.
2. Heat the oil in a 10-inch cast iron or ovenproof skillet over medium-high. Add the onion, carrots and celery, season with salt and pepper, and cook until tender, about 5 minutes.
3. Add the mushrooms, season, and cook until softened, about 5 minutes. Stir in the tomato paste, garlic and thyme and cook until fragrant, 1–2 minutes.
4. Stir in the lentils, season, then add the wine and bring to a boil, scraping up any browned bits. Cook until the wine is nearly evaporated, about 1–2 minutes. Add the broth, bring to a boil, and cook until slightly thickened, about 1 minute. Remove from heat and stir in the sherry vinegar, sugar and truffle oil if using. Taste and adjust seasoning.
5. Spoon the cauliflower purée over the filling, spreading it into an even layer. Sprinkle with the cheese and broil on the top rack until bubbling and golden, about 5 minutes. Let rest 5 minutes before serving.

• The cauliflower purée can be made up to one day ahead. Bring it to room temperature before using.
• To cook dried lentils: place 1 cup green lentils (Le Puy lentils are ideal) in a medium pot with 4 cups water and optional aromatics (a smashed garlic clove, a parsley sprig or a bay leaf). Bring to a boil, reduce to a simmer, and cook 15–20 minutes until tender but still holding shape. Drain. This will yield more lentils than the recipe requires — save the remainder for salads or freeze for later.